There is no such thing as a left libertarian. Leftist philosophy requires govm't control of economic operations by directing those operations, govm't distribution of wealth according to some govm't scheme and govm't control of property as in wealth.
Libertarian philosophy holds that govm'ts only justification for existence is to protect rights and sanction violations against those rights. That means that such activities as regulation of the Free market can only go sofar as to provide fairness. Fairness is judged on whether, or not, fraud and coericon are present. Govm't control and direction for any other reason is not allowed. Friedman and Heyak would fit here, that's why they don't appear on the anarchist's site. That site only promotes hard core leftists.
The site you provided is an anarchist site, that's it. There's no truth to what they say. They have usurped the word libertarian, in a fashion similar to the way the socialists usurped the word liberal from it's prior meaning. The reason they did that is for obfuscation purposes. ie. War is peace and liberty is domination. The correct word for the "left libertarian" described on that site is liberal.
Into the memory hole, spunkets?
They have usurped the word libertarian
Backwards.